The identification of factors effective in modulating diabetes and glucose metabolism in subjects needing such intervention such as, for example, persons with diabetes (type I or type II) is needed. Persons suffering from defects in glucose metabolism and diabetes have limited treatment options at the present time. Current research is focused on the identification and synthesis of, for example, small molecules suitable for intervention. Exercise is known to modulate glucose metabolism and have modulating effects on diabetes in patient subjects. [Kourtoglou, Diabetes. Res. Clin. Pract. 93 Suppl 1:S73-7 (2011); Brandt and Pedersen, J. Biomed. Biotechnol. 2010: 520258-64 (2010); Goodyear and Kahn, Ann. Rev. Med. 49: 235-261 (1998); Sigel et al., Diabetes Care 27: 2518-39 (2004)]. Still, little work has been directed towards the physiological basis for these observations. What is needed are methods for the identification of native physiological pathways and factors that mediate glucose control and metabolism in vivo.